JP2014037508A - Conductive composition and conductive film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive composition excellent in permeability into a dielectric layer, and to provide a solid electrolytic capacitor low in leakage current by using the conductive composition.SOLUTION: A conductive composition (A) contains a substituted polythiophene (P) and a phosphoric acid and/or a phosphoric acid ester (Q). In the substituted polythiophene (P), at least part of a thiophene repeating unit is a thiophene repeating unit (α) in which the 3-position and/or the 4-position of a thiophene ring is substituted with at least one group selected from the group consisting of: a polyether group (a) represented by general formula (1); an alkoxy group (b); an alkoxyalkyl group (c); and an alkyl group or an alkyl group (d) obtained by substituting a hydrogen atom of the alkyl group with the polyether group (a).

Description

  The present invention relates to a conductive composition. More specifically, a conductive composition containing a conductive polymer and a dopant having a specific chemical structure; a conductive film made of the conductive composition; an electrode for a solid electrolytic capacitor using the conductive composition; The present invention relates to a solid electrolytic capacitor using a conductive composition.

  In recent years, attempts have been made to develop conductive polymer compounds that can impart conductivity at low temperatures on flexible substrates, and application to conductive functional materials, light-emitting functional materials, photoelectric conversion functional materials, and the like is expected.

  Conventionally, many examples of the use of a compound having a sulfonic acid group as a dopant have been reported as a conductive polymer that gives a conductive film (see, for example, Patent Document 1).

Patent Document 1 proposes a water-dispersed colloidal coating liquid using polystyrene sulfonic acid as a dopant. However, this coating solution is extremely hydrophilic, and the conductive film produced using this coating solution has high hygroscopicity, and the strongly acidic hydrogen ions generated by this moisture absorption corrode metals and the like that come into contact with the coating. There are problems such as. Moreover, the electrical conductivity of the conductive film obtained by this coating liquid is about 100 S / cm, and it cannot be said that it is enough as an electrical conductivity required in order to apply to an electroconductive functional material.

  Moreover, the usage example of the compound which has groups other than a sulfonic acid group as a dopant for the purpose of the application to an electroconductive functional material is also reported (for example, refer patent document 2).

Patent Document 2 proposes a coating solution of a conductive polymer solution or a dispersion using phosphoric acid or a phosphate ester as a dopant. Although this coating solution has been proposed for solid electrolytic capacitors, it cannot be said that the performance such as leakage current is sufficient because of its poor permeability to the dielectric layer.

Japanese Patent Laid-Open No. 7-90060 JP 2001-155964 A

  The present invention has been made in view of the above problems, and the present invention provides a conductive composition having good permeability to a dielectric layer, and a solid electrolytic capacitor having a low leakage current using the conductive composition. The purpose is to provide.

［式中、ＯＲ^１は炭素数２〜４のオキシアルキレン基を表し、Ｒ^２は炭素数１〜１５のアルキル基を表し、ｋは１〜９の整数である。］ As a result of intensive studies to achieve the above object, the present inventors have reached the present invention.
That is, in the present invention, at least a part of the thiophene repeating unit is
A polyether group (a) represented by the following general formula (1),
An alkoxy group (b) having 1 to 15 carbon atoms,
An alkoxyalkyl group (c) having 1 to 19 carbon atoms and an alkyl group having 1 to 15 carbon atoms, or an alkyl group (d) in which a hydrogen atom of the alkyl group is substituted with the polyether group (a)
A substituted polythiophene (P) which is a thiophene repeating unit (α) substituted at the 3-position and / or 4-position of the thiophene ring with at least one group selected from the group consisting of: and phosphoric acid and / or phosphate ester (Q It is an electroconductive composition (A) characterized by containing).

Wherein, OR ¹ represents an oxyalkylene group having 2 to 4 carbon atoms, ^{R 2} represents an alkyl group having 1 to 15 carbon atoms, k is an integer of 1 to 9. ]

  The conductive composition of the present invention has good permeability to a substrate (dielectric layer) of an etched metal or the like, and the solid electrolytic capacitor produced using the conductive composition has a low leakage current. Play.

  In the conductive composition (A) of the present invention, at least a part of the thiophene repeating units is a polyether group (a), an alkoxy group (b), an alkoxyalkyl group (c), or an alkyl group (d). It contains a substituted polythiophene (P) which is a thiophene repeating unit (α) substituted at the 3-position and / or 4-position of the thiophene ring, and phosphoric acid and / or phosphate ester (Q) as a dopant.

As said polyether group (a), it has the repeating unit which is shown by the said General formula (1), and consists of a C2-C4 oxyalkylene group, The repeating unit number is 1-9, One terminal Is a polyether group which is an alkoxy group having 1 to 15 carbon atoms.
Examples of the oxyalkylene group having 2 to 4 carbon atoms include an oxyethylene group, an oxypropylene group, and oxybutylene.

  Examples of the terminal alkoxy group having 1 to 15 carbon atoms include methoxy group, ethoxy group, propoxy group, isopropoxy group, n-, iso-, sec- or tert-butoxy group, pentyloxy group, hexyloxy group, heptyloxy Group, octyloxy group, 2-ethylhexyloxy group, nonyloxy group, decyloxy group, undecyloxy group, dodecyloxy group, tridecyloxy group, tetradecyloxy group and pentadecyloxy group.

  As said alkoxy group (b), the C1-C15 alkoxy group similar to what was illustrated by the said polyether group (a) is mentioned.

  As said alkoxyalkyl group (c), the C1-C4 alkyl group substituted by the C1-C15 alkoxy group is mentioned. Examples of the alkoxy group having 1 to 15 carbon atoms include those exemplified in the polyether group (a). Examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, n- or Examples thereof include an iso-propyl group and an n-, sec-, iso- or tert-butyl group.

As the alkyl group (d) of the thiophene repeating unit (α), a linear or branched alkyl group having 1 to 15 carbon atoms, for example, a methyl group, an n- or iso-propyl group, n-, iso-, sec- Or tert-butyl group, n- or iso-pentyl group, cyclopentyl group, n- or iso-hexyl group, cyclohexyl group, n- or iso-heptyl group, n- or iso-octyl group, 2-ethylhexyl group, n -Or iso-nonyl, n- or iso-decyl, n- or iso-undecyl, n- or iso-dodecyl, n- or iso-tridecyl, n- or iso-tetradecyl and n- or An iso-pentadecyl group is mentioned.
The alkyl group (d) may be an alkyl group in which a hydrogen atom of the alkyl group is substituted with the polyether group (a).

  As the thiophene repeating unit (α) of the substituted polythiophene (P) in the present invention, the repeating unit (α1) represented by the following general formula (2) and the following general formula (3) are preferable from the viewpoint of conductivity. It is a repeating unit (α3) represented by the repeating unit (α2) or the following general formula (4).

OR ³ in the general formula (2) and OR ⁶ in the general formula (3) each independently represent an oxyethylene group or an oxypropylene group, and an oxyethylene group is preferred from the viewpoint of conductivity.

R ⁴ , R ⁷ and R ⁸ in the general formulas (2) to (4) are each independently a linear or branched alkyl group having 1 to 12 carbon atoms (for example, a methyl group, n- or iso-propyl). Group, n-, iso-, sec- or tert-butyl group, n- or iso-pentyl group, cyclopentyl group, n- or iso-hexyl group, cyclohexyl group, n- or iso-heptyl group, n- or iso -Octyl group, 2-ethylhexyl group, n- or iso-nonyl group, n- or iso-decyl group, n- or iso-undecyl group and n- or iso-dodecyl group).

In the general formula (2), when n is 1 or more, R ⁴ is preferably a linear or branched alkyl group having 1 to 6 carbon atoms, more preferably 1 to 4 carbon atoms, from the viewpoint of conductivity. A linear or branched alkyl group.
When n is 0, R ⁴ is preferably a linear or branched alkyl group having 3 to 12 carbon atoms, more preferably a linear or branched alkyl group having 6 to 12 carbon atoms, from the viewpoint of conductivity. It is.

In the general formula (3), when m is 1 or more, R ⁷ is preferably a linear or branched alkyl group having 1 to 6 carbon atoms, more preferably 1 to 4 carbon atoms, from the viewpoint of conductivity. A linear or branched alkyl group.
When m is 0, R ⁷ is preferably a linear or branched alkyl group having 3 to 12 carbon atoms, more preferably a linear or branched alkyl group having 6 to 12 carbon atoms, from the viewpoint of conductivity. It is.

R ⁸ is preferably a linear or branched alkyl group having 3 to 12 carbon atoms, more preferably a linear or branched alkyl group having 6 to 12 carbon atoms, from the viewpoint of solvent solubility and conductivity. .

R ⁵ in the general formula (3) is a linear or branched alkylene group having 1 to 4 carbon atoms (for example, a methylene group, an ethylene group, a 1,2- or 1,3-propylene group, and a 1,2--1, , 3-, 2,3- or 1,4-butylene group), preferably from the viewpoint of solvent solubility and conductivity, a linear or branched alkylene group having 1 to 3 carbon atoms, more preferably , A methylene group or an ethylene group.

  N and m in the general formula (2) or (3) are each independently an integer of 0 to 5. n is preferably 1 to 5 and more preferably 2 to 5 from the viewpoints of solvent solubility and conductivity. m is preferably 0 to 4 from the viewpoint of solvent solubility and conductivity, and more preferably m is 0 to 3.

  The substituted polythiophene (P) in the present invention is preferably a polymer consisting only of the thiophene repeating unit (α). Moreover, the thiophene repeating unit which is not substituted may be included.

  The content of the thiophene repeating unit (α) in the substituted polythiophene (P) is preferably 50 to 100% by weight, more preferably 60 to 100%, based on the weight of the substituted polythiophene (P), from the viewpoint of solvent solubility. % By weight, particularly preferably 70 to 100% by weight.

  The substituted polythiophene (P) in the present invention can be synthesized by a known method such as anionic polymerization or oxidative polymerization of monomers corresponding to the respective repeating units.

As a monomer corresponding to the thiophene repeating unit (α), the 3-position and / or 4-position of the thiophene ring is a polyether group (a), an alkoxy group (b), an alkoxyalkyl group (c) or an alkyl group (d). And thiophene substituted at the 2- and 5-positions with a halogen atom (preferably a bromine atom).
Examples of the monomer corresponding to the unsubstituted thiophene repeating unit include thiophene and thiophene substituted at the 2nd and 5th positions with a halogen atom (preferably a bromine atom).

  The content of the substituted polythiophene (P) in the conductive composition (A) is preferably 0.1 to 20% by weight, more preferably based on the weight of the conductive composition (A) from the viewpoint of solubility. 1.0 to 6.0% by weight. When there is too much content of substituted polythiophene (P), since an aggregate will arise and coating property will deteriorate, it is unpreferable. Moreover, when there is too little content of substituted polythiophene (P), since formation of a uniform electroconductive film becomes difficult, it is unpreferable.

  The stereoregularity (Regorregularity: RR) of the substituted polythiophene (P) in the present invention is usually 50% or more, preferably 80% or more, more preferably 90% or more from the viewpoint of conductivity.

The definition of stereoregularity (RR) in the present invention will be described below.
As shown in the following general chemical formula, the type of bond of the substituted polythiophene (P) is HT-HT bond (B1), TT-HT bond (B2), HT-HH bond (B3), TT-HH bond (B4). There are four types. Here, HT is an abbreviation for head to tail, TT is an abbreviation for tail to tail, and HH is an abbreviation for head to head.

  R in the chemical formulas of the above four bond types independently represents a polyether group (a), an alkoxy group (b), an alkoxyalkyl group (c) or an alkyl group (d).

The stereoregularity (RR) of the substituted polythiophene (P) in the present invention is defined by the ratio (%) of the HT-HT bond (B1) in the substituted polythiophene (P), and is calculated by the following mathematical formula (1).
Stereoregularity (RR) = B1 × 100 / (B1 + B2 + B3 + B4) (1)
Where B1: HT-HT bond number, B2: TT-HT bond number, B3: HT-HH bond number, B4: TT-HH bond number.

Specifically, the protons possessed by these bonds each show a specific chemical shift (δ) by nuclear magnetic resonance ( ¹ H-NMR), and are calculated from the integrated values of chemical shifts corresponding to the four types of bonds. can do.
In the case of the polythiophene derivative having the repeating unit (α3) represented by the general formula (3), specifically, HT-HT bond (B1): δ = 6.98, TT-HT bond (B2): δ = 7.00, HT-HH bond (B3): δ = 7.02, TT-HH bond (B4): δ = 7.05. Therefore, the integral values S1, S2, S3, S4 in the chemical shift specific to (B1), (B2), (B3), (B4) are calculated, and the integral value in the chemical shift specific to (B1) with respect to the sum of the integral values. Stereoregularity (RR) is calculated from the ratio (%) of S1 using the following mathematical formula (2).
Stereoregularity (RR) = S1 × 100 / (S1 + S2 + S3 + S4) (2)
The ¹ H-NMR measurement was performed under the conditions of measuring solvent: deuterated chloroform, measuring temperature: 27 ° C. using a measuring instrument: AVANCEIII400 type digital NMR [manufactured by Bruker Biospin Co., Ltd.]. .

The conductive composition (A) of the present invention contains phosphoric acid and / or phosphate ester (Q) as a dopant. (Q) is preferably phosphoric acid from the viewpoint of permeability to the substrate.
Examples of phosphate esters include compounds represented by the following general formula (6). Monoesters and diesters may be used alone or in combination.

［ｎ、ｍは１または２であって、ｎ＋ｍ＝３を満足し、Ｒは炭素数１〜３０の有機基である。］
Ｒは炭素数１〜３０、好ましくは１〜２０のアルキル基、アリール基、アルケニル基等が挙げられる。
アルキル基としてはメチル、エチル、ｎ-ブチル、オクチル（ｎ−オクチル、２−エチルヘキシル）、ステアリル等、アリール基としてはフェニル、２−メチルフェニル等、アルケニル基としてはビニル等が挙げられる。

[N and m are 1 or 2, satisfying n + m = 3, and R is an organic group having 1 to 30 carbon atoms. ]
R includes an alkyl group having 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms, an aryl group, and an alkenyl group.
Examples of the alkyl group include methyl, ethyl, n-butyl, octyl (n-octyl, 2-ethylhexyl), stearyl, the aryl group includes phenyl, 2-methylphenyl, and the alkenyl group includes vinyl.

Examples of the phosphoric acid monoester include monomethyl phosphate, monoethyl phosphate, mono-n-butyl phosphate, monooctyl phosphate, monophenyl phosphate, monostearyl phosphate, monocresyl phosphate, and the like.
Examples of the phosphoric acid diester include dimethyl phosphate, diethyl phosphate, di-n-butyl phosphate, dioctyl phosphate, diphenyl phosphate, distearyl phosphate, and dicresyl phosphate.

The substituted polythiophene (P), which is a conductive polymer, donates electrons to the phosphoric acid and / or phosphate ester (Q) as a dopant to form a charge transfer complex together with (Q).
Since this charge transfer complex exhibits conductivity as an electron carrier, the concentration of phosphoric acid and / or phosphate ester (Q) is preferably high, but if it is excessive, the conductivity is lowered. Accordingly, the amount of phosphoric acid and / or phosphate ester (Q) used is preferably 5 to 1000% by weight, more preferably 10 to 800% by weight, based on the substituted polythiophene (P).

The conductive composition of the present invention may further contain an organic solvent. After applying the conductive composition (A) to the substrate (or immersing the substrate in the conductive composition (A)), heat treatment is performed as necessary to remove the organic solvent to produce a conductive film. be able to.
As the organic solvent (S), a good solvent (S1) for the substituted polythiophene (P) and a good solvent (S2) for phosphoric acid and / or phosphate ester (Q) are used in order to obtain a uniform solution without precipitates. It is preferable to use in combination.

  Examples of the good solvent (S1) of the substituted polythiophene (P) include chlorine-based, amide-based, ether-based, aromatic hydrocarbon-based, alcohol-based, ketone-based and sulfur-based solvents having 1 to 10 carbon atoms. Those are chloroform, methylene chloride, dimethylformamide, N-methylpyrrolidone, tetrahydrofuran (hereinafter abbreviated as THF), 1,3-dioxolane, toluene, methanol, acetone, methyl ethyl ketone, γ-butyrolactone, cyclopentanone, cyclohexanone, dimethyl. Examples thereof include sulfoxide and a mixture thereof.

Examples of the good solvent (S2) for phosphoric acid and / or phosphate ester (Q) include methanol, ethanol, 2-propanol, ethylene glycol, N-methylpyrrolidone, THF, γ-butyrolactone, and cyclopentanone. Of these, methanol, ethanol, 2-propanol and γ-butyrolactone are preferable from the viewpoint of dissolution stability.

In order to obtain a uniform solution when the substituted polythiophene (P) and phosphoric acid and / or phosphate ester (Q) are mixed, the (S1) solvent solution of the substituted polythiophene (P) and phosphoric acid and / or phosphate ester It is preferable to mix after preparing (S2) solvent solutions of (Q).
As a density | concentration of the solvent solution of substituted polythiophene (P), 0.1 to 10 weight% is preferable.
As a density | concentration of the solvent solution of phosphoric acid and / or phosphate ester (Q), 1 to 80 weight% is preferable.

  When producing a conductive film using the conductive composition (A) of the present invention, it is necessary to remove these solvents. In the case of a solvent having a low boiling point, the solvent is removed by natural drying at room temperature or heat drying by circulating drying, but in the case of a solvent having a high boiling point, heat drying by a vacuum dryer is preferable.

  The conductive composition (A) of the present invention is particularly suitable for a solid electrolytic capacitor electrode. A solid electrolytic capacitor is a capacitor in which an oxide film such as aluminum is etched to form a porous film, and a conductive polymer layer is formed on this surface to form an electrode (cathode). In conventional methods, such as a method of applying a dispersion containing a precursor monomer of a polymer, or a method of applying a polymer obtained by dissolving polypyrrole of a conductive polymer in a solvent using dodecylbenzenesulfonic acid as a dopant, the production efficiency of the capacitor However, there is a problem that the capacity of the capacitor cannot be increased efficiently.

  In contrast, since the conductive composition (A) of the present invention is completely dissolved in an organic solvent and has high conductivity, the porous polymer film is impregnated with a conductive polymer in a simple process. Furthermore, since it has excellent adhesion to the porous body film, the capacitor capacity can be increased efficiently. Moreover, since the adhesiveness to the porous body film is excellent, the internal resistance of the capacitor can be lowered.

  Examples of the method for applying the conductive composition (A) to the substrate include spin coating, drop casting, dip coating, and a method of impregnating the conductive composition (A) with the substrate. Examples of the substrate include plastic, glass, metal, rubber, ceramics, and paper.

  From the viewpoint of conductivity, the thickness of the film obtained by drying the conductive composition (A) formed on the substrate surface is preferably 0.05 to 100 μm, more preferably 0.1 to 50 μm. It is. If the coating is thinner than 0.05 μm, sufficient conductivity may not be obtained. On the other hand, if the thickness exceeds 100 μm, there may be a problem that cracking or peeling tends to occur during formation.

  In order to obtain a highly conductive conductive film using the conductive composition (A) of the present invention, the heat treatment temperature is preferably 100 to 190 ° C, more preferably 110 to 170 ° C. When the temperature is lower than 100 ° C., sufficient strength and conductivity may not be obtained. Moreover, when the temperature is higher than 190 ° C., the conductivity may be deteriorated.

  The heating time is appropriately selected according to the heating temperature and the concentration of the substituted polythiophene (P) in the conductive composition (A), but is usually 0.5 to 8 hours, preferably 1 to 4 hours. is there. When heating time is too short, the electroconductivity of the electroconductive film obtained from said electroconductive composition (A) may not be enough.

  The conductive composition (A) of the present invention is useful because it is excellent in permeability to a substrate by addition of (Q) and excellent in conductivity, and a conductive film can be produced only by simple coating. . In particular, it is useful because a capacitor film can be efficiently increased by impregnating a porous film with a conductive polymer by a simple process, and a solid electrolytic capacitor having a low internal resistance can be produced.

  Hereinafter, although an example and a comparative example explain the present invention further, the present invention is not limited to these. Hereinafter, a part shows a weight part.

<Production Example 1>: Synthesis of poly [3- (1,4,7,10-tetraoxaundecyl) thiophene] (P-1) (1) 3- (1,4,7,10-tetraoxaun Synthesis of (decyl) thiophene:
6.0 parts of sodium hydride (dispersed in paraffin at a concentration of 60% by weight) was dispersed in 50 parts of N, N-dimethylformamide, and 36.9 parts of triethylene glycol monomethyl ether was added dropwise thereto. The reaction solution foamed and became cloudy. When foaming subsided, 24.5 parts of 3-bromothiophene and 2.0 parts of copper (I) bromide were sequentially added to the reaction solution. The reaction solution was heated to 110 ° C. and reacted for 2 hours. After completion of the reaction, the mixture was allowed to cool to room temperature, 50 parts of a 1 mol / L ammonium chloride aqueous solution was added, the mixture was transferred to a separatory funnel using 50 parts of ethyl acetate, and the aqueous layer was separated. Further, the organic layer was washed twice with 30 parts of distilled water, and then ethyl acetate was distilled off to obtain 34.0 parts of 3- (1,4,7,10-tetraoxaundecyl) thiophene.

(2) Synthesis of 2,5-dibromo-3- (1,4,7,10-tetraoxaundecyl) thiophene:
7.4 parts of the above 3- (1,4,7,10-tetraoxaundecyl) thiophene and 10.7 parts of N-bromosuccinimide were dissolved in 40 parts of THF and reacted at room temperature for 2 hours. The precipitate was removed with a glass filter using 50 parts of ethyl acetate, and THF and ethyl acetate were distilled off. The obtained mixture was purified with a silica gel column to obtain 10.5 parts of 2,5-dibromo-3- (1,4,7,10-tetraoxaundecyl) thiophene.

(3) Synthesis of poly [3- (1,4,7,10-tetraoxaundecyl) thiophene]:
After dissolving 8.1 parts of 2,5-dibromo-3- (1,4,7,10-tetraoxaundecyl) thiophene in 150 parts of THF, 21 parts of a 1 mol / L methylmagnesium bromide THF solution was added. And reacted at 75 ° C. for 30 minutes. To the reaction solution, 0.1 part of [1,3-bis (diphenylphosphino) propane] -dichloronickel (II) was added, and the mixture was further reacted at 75 ° C. for 5 hours. The reaction solution was allowed to cool to room temperature, and 20 parts of methanol was added. After distilling off the solvent, the reaction mixture was transferred to a Soxhlet extractor and washed in order with 150 parts of methanol and 150 parts of hexane. Finally, the residue was extracted with 150 parts of chloroform, and the solvent was distilled off to obtain 3.1 parts of poly [3- (1,4,7,10-tetraoxaundecyl) thiophene] (P-1). . The stereoregularity calculated by the aforementioned method using ¹ H-NMR was 96.3%.

<Production Example 2>: Synthesis of poly [3- (1,4,7,10,13,16,19-heptaoxaeicosyl) thiophene] (P-2) In (1) of Production Example 1, triethylene was synthesized. Poly [3- (1, 4, 7,10,13,16,19-heptaoxaeicosyl) thiophene] (P-2) 2.9 parts. In addition, when changing triethylene glycol monomethyl ether to hexaethylene glycol monomethyl ether, the molar ratio of the reaction components and the weight ratio of the non-reaction components (solvents, etc.) are the same as those in Production Example 1. The experiment was performed with the amount adjusted.

<Production Example 3>: Synthesis of poly (3-heptyloxythiophene) (P-3) In Production Example 1 (1), the same procedure as in Production Example 1 except that triethylene glycol monomethyl ether was changed to 1-heptanol. Experimental operation was performed to obtain 2.7 parts of poly (3-heptyloxythiophene) (P-3) having a stereoregularity of 95.4%.

<Production Example 4>: Synthesis of poly {3- (2,5-dioxaheptyl) thiophene} (P-4) (1) Synthesis of 3-bromomethylthiophene:
3-methylthiophene [Tokyo Chemical Industry Co., Ltd.] 5 parts (50.9 mmol), N-bromosuccinimide 9.97 parts (56.0 mmol), dibenzoyl peroxide [Tokyo Chemical Industry Co., Ltd.] 0. After 12 parts (0.50 mmol) was dissolved in 30 parts of benzene, the temperature was raised to 100 ° C. and reacted for 4 hours. After completion of the reaction, the mixture was allowed to cool to room temperature, 30 parts of 1M aqueous sodium thiosulfate solution was added, and the mixture was transferred to a separatory funnel, and then the aqueous layer was separated. Further, the organic layer was washed twice with 30 parts of distilled water, and then benzene was distilled off to obtain 6.32 parts (35.7 mmol) of 3-bromomethylthiophene.

(2) Synthesis of 3- (2,5-dioxaheptyl) thiophene:
3.54 parts (39.3 mmol) of 2-ethoxyethanol was dissolved in 15 parts of THF, and sodium hydride (60% paraffin dispersion) was added thereto. 6.32 parts (35.7 mmol) of the above 3-bromomethylthiophene was dissolved in 15 parts of THF, added dropwise over 2 hours, then heated to 100 ° C. and reacted for 4 hours. After completion of the reaction, the mixture was allowed to cool to room temperature, 30 parts of distilled water was added, and the mixture was transferred to a separatory funnel, and the aqueous layer was separated. Further, the organic layer was washed twice with 30 parts of distilled water, THF was distilled off, and the resulting mixture was purified with a silica gel column to obtain 5.68 parts of 3- (2,5-dioxaheptyl) thiophene. (30.5 mmol) was obtained.

(3) Synthesis of 2,5-dibromo-3- (2,5-dioxapentyl) thiophene:
5.68 parts (30.5 mmol) of 3- (2,5-dioxaheptyl) thiophene and 11.9 parts (67.1 mmol) of N-bromosuccinimide were dissolved in THF and reacted at room temperature for 2 hours. . The precipitate was removed with a glass filter using 50 parts of ethyl acetate, and THF and ethyl acetate were distilled off. The obtained mixture was purified with a silica gel column to obtain 8.11 parts (23.6 mmol) of 2,5-dibromo-3- (2,5-dioxaheptyl) thiophene.

(4) Synthesis of poly {3- (2,5-dioxaheptyl) thiophene}:
After dissolving 8.11 parts (23.6 mmol) of the above 2,5-dibromo-3- (2,5-dioxaheptyl) thiophene in 30 parts of THF, 25 parts of methylmagnesium bromide THF solution was added, and the mixture was heated at 75 ° C. The reaction was performed for 30 minutes. To the reaction solution, 0.127 part of [1,3-bis (diphenylphosphino) propane] -dichloronickel (II) was added, and the reaction was further continued for 2 hours at 75 ° C. The reaction solution was allowed to cool to room temperature, and 5 parts of methanol was added. The reaction mixture was transferred to a Soxhlet extractor and washed sequentially with 150 parts of methanol and 150 parts of hexane. Finally, the residue was extracted with 150 parts of chloroform, the solvent was distilled off, and poly {3- (2,5-dioxaheptyl) thiophene} (P-4) 2 having a stereoregularity of 94.6% .85 parts were obtained.

<Production Example 5>: Synthesis of poly (3-dodecylthiophene) (P-5) In Production Example 1, (3), 2,5-dibromo-3- (1,4,7,10-tetraoxaundecyl) ) Poly (3-dodecylthiophene) having the same stereoregularity as 96.4% except that thiophene was changed to 2,5-dibromo-3-dodecylthiophene (manufactured by Aldrich). ) (P-5) 3.5 parts were obtained.

<Examples 1 to 12>
Substituted polythiophenes (P-1) to (P-5) obtained in Production Examples 1 to 5, phosphoric acid (manufactured by Nacalai Tesque) as a dopant, mono (2-ethylhexyl) phosphate (Nacalai Tesque) Manufactured), distearyl phosphate (manufactured by Nacalai Tesque), organic solvent (S1), and organic solvent (S2) are blended as shown in Table 1, and the conductive composition (A-1)- A solution of (A-12) was obtained.
Specifically, a substituted polythiophene is dissolved in an organic solvent (S1) to prepare a solution, and a solution is prepared by dissolving phosphoric acid and / or phosphate ester (Q) in an organic solvent (S2). Both solutions were mixed immediately before the preparation step to prepare a conductive composition solution.

<Comparative Example 1>
Known as an aqueous dispersion of polythiophene, “PEDOT / PSS” (Baytron-P; manufactured by HC Starck Co .; 3,4-ethylenedioxythiophene is polymerized in a high molecular weight polystyrenesulfonic acid aqueous solution. The conductive polymer) was used as an aqueous dispersion of the comparative conductive composition (A′-1) as it was.

<Comparative example 2>
A 0.4% aqueous dispersion of polyethylene dioxythiophene was added to F.M. A conductive composition for comparison, prepared by the method disclosed in Jonas et al., Synthetech Metals (issued by Elsevier), Vol. 85, No. 1397, and blending phosphoric acid and organic solvent (S2) shown in Table 1 An aqueous dispersion of (A′-2) was obtained.

<Comparative Example 3>
In Comparative Example 2, the conductive composition for comparison (A′-3) was compared with Comparative Example 2 except that 3.3 parts of phosphoric acid was replaced with 3.3 parts of mono (2-ethylhexyl) phosphate. An aqueous dispersion was obtained.

<Comparative Example 4>
In Comparative Example 2, an aqueous dispersion of the conductive composition for comparison (A′-4) was prepared in the same manner as in Comparative Example 2 except that 3.3 parts of phosphoric acid was replaced with 3.3 parts of distearyl phosphate. Obtained.

<Comparative Example 5>
In Example 1, except that 3.3 parts of phosphoric acid was replaced with 3.3 parts of sulfuric acid (manufactured by Sasaki Chemical Co., Ltd.), a conductive composition for comparison (A′-5) in the same manner as in Example 1. ) Was obtained.

Solutions of conductive compositions (A-1) to (A-12) of Examples 1 to 12, and solutions and water dispersions of comparative conductive compositions (A′-1) to (A′-5) Using the liquid, the contact angle on the glass substrate was measured using a fully automatic contact angle meter (manufactured by Kyowa Interface Science Co., Ltd.) in accordance with JIS K-2396. The results are shown in Table 1. The lower the contact angle, the better the wetting. In addition, it is thought that the wetting behavior with respect to the glass substrate of the said conductive composition solution shows the behavior similar to the wetting with respect to a dielectric material layer.

[Evaluation method of capacitor characteristics]
(1) Preparation of dielectric film on anode An aluminum etched foil (size: 4 × 3.3 mm) as an anode metal is immersed in a 3% by weight aqueous solution of ammonium adipate and a constant current constant voltage power supply device is used. After raising from 0 V to 20 V under the condition of 0.53 mA / sec, a constant voltage of 20 V was applied for 40 minutes for chemical conversion treatment to form a dielectric film made of an oxide film on the surface of the aluminum etched foil. This was washed with running deionized water for 10 minutes and then dried at 105 ° C. for 5 minutes to produce an anode composed of an anode metal and a dielectric film.

(2) Production of Electrode for Solid Electrolytic Capacitor Solution of conductive compositions (A-1) to (A-12) and comparative conductive compositions (A′-1) to (A′-5) Then, the anode was dipped in the aqueous dispersion and pulled up, followed by drying under reduced pressure at room temperature for 30 minutes to form an electrolyte layer and produce a solid electrolytic capacitor electrode.

(3) Production of Electrolytic Capacitor A carbon paste [“Bunny Height FU” manufactured by Nippon Graphite Co., Ltd.] is applied on the electrolyte layer obtained above, dried, and further silver paste [manufactured by Nippon Graphite Co., Ltd.]. “Everyome ME”] was applied and dried to form a cathode. Lead wires were pulled out from the silver paste, and terminals were connected.

(4) Measurement and evaluation The initial value of the leakage current of the obtained electrolytic capacitor was measured. The initial value of the leakage current is a current value 30 seconds after 6.3 V application. The results are shown in Table 1.

As the contact angle results in Table 1 indicate, the conductive composition solutions of Examples 1 to 12 of the present invention are dielectrics compared to the comparative conductive composition solutions (or dispersions) of Comparative Examples 1 to 5. It is considered that the layer has good wetting and, as a result, good permeability.
Moreover, as the result of the leakage current of Table 1 shows, the solid electrolytic capacitor created using the electrically conductive composition of Examples 1-12 of this invention is the comparative electrically conductive composition solution of Comparative Examples 1-5 ( It was also found that the leakage current was lower than that of the solid electrolytic capacitor prepared using the dispersion liquid.
In Comparative Examples 2 to 4, phosphoric acid or phosphoric acid ester (Q) is contained, but the permeability to the dielectric layer is poor (Q) healing effect (formation of an oxide film to eliminate defects in the dielectric layer) It is thought that the effect of repairing) has not been demonstrated.

  The conductive composition (A) of the present invention is excellent in permeability to a substrate by addition of phosphoric acid and / or phosphate ester (Q), and is excellent in conductivity, and can be conductive only by simple coating. Since a film can be produced, application to various conductive functional materials can be expected. In particular, it is useful as an electrode for a solid electrolytic capacitor.

Claims (9)

At least some of the thiophene repeat units are
A polyether group (a) represented by the following general formula (1),
An alkoxy group (b) having 1 to 15 carbon atoms,
An alkoxyalkyl group (c) having 1 to 19 carbon atoms and an alkyl group having 1 to 15 carbon atoms, or an alkyl group (d) in which a hydrogen atom of the alkyl group is substituted with the polyether group (a)
A substituted polythiophene (P) which is a thiophene repeating unit (α) substituted at the 3-position and / or 4-position of the thiophene ring with at least one group selected from the group consisting of: and phosphoric acid and / or phosphate ester (Q ) Containing the conductive composition (A).

Wherein, OR ¹ represents an oxyalkylene group having 2 to 4 carbon atoms, ^{R 2} represents an alkyl group having 1 to 15 carbon atoms, k is an integer of 1 to 9. ] The conductive composition according to claim 1, comprising 5 to 1000% by weight of phosphoric acid and / or phosphate ester (Q) based on the weight of the substituted polythiophene (P). The thiophene repeating unit (α) is a repeating unit (α1) represented by the general formula (2), a repeating unit (α2) represented by the general formula (3) or a repeating unit represented by the general formula (4). The conductive composition according to claim 1, which is (α3).

[Wherein, OR ³ and OR ⁶ each independently represent an oxyethylene group or an oxypropylene group, and R ⁴ , R ⁷ and R ⁸ each independently represent a linear or branched alkyl group having 1 to 12 carbon atoms. , R ⁵ represents a linear or branched alkylene group having 1 to 4 carbon atoms, and n and m are each independently an integer of 0 to 5. ] In the repeating unit (α1), OR ³ in the general formula (2) is an oxyethylene group, and when n is 0, R ⁴ is a linear or branched alkyl group having 3 to 12 carbon atoms, n Is 1 or more, R ⁴ is a linear or branched alkyl group having 1 to 6 carbon atoms, and the repeating unit (α2) is represented by R ⁵ in the general formula (3) having 1 to 1 carbon atoms. 3 is an alkylene group, OR ⁶ is an oxyethylene group, m is 0, R ⁷ is a linear or branched alkyl group having 3 to 12 carbon atoms, and m is 1 or more. R ⁷ is a linear or branched alkyl group having 1 to 6 carbon atoms, and the repeating unit (α3) is a linear or branched R ⁸ having 3 to 12 carbon atoms in the general formula (4). The conductive composition according to claim 3, which is an alkyl group of   Content of the said thiophene repeating unit ((alpha)) in the said substituted polythiophene (P) is 50-100 weight% in substituted polythiophene (P), The electrically conductive composition of any one of Claims 1-4. .   The electrically conductive composition according to any one of claims 1 to 5, wherein the stereoregularity defined by a percentage of head-to-tail-head-to-tail bonds in the substituted polythiophene (P) is 90% or more. The electroconductive film which consists of an electroconductive composition of any one of Claims 1-6.   The electrode for solid electrolytic capacitors formed using the electroconductive composition of any one of Claims 1-6.   The solid electrolytic capacitor which uses the electrically conductive composition of any one of Claims 1-6.